47 2 * * Oliver . — The Ovules of the older Gy mno sperms . 
Concurrently the embryo-sac has extended down (as repre- 
sented by arrows in Fig. n) and occupied all the available 
space. To interpret the facts literally the tracheal plate 
(at the base of the nucellus in Fig. io) has become stretched 
and split into a ring, and the embryo-sac has obtained an 
outle by extending right through this ring (Fig. n). In the 
seed of Torreya the tracheal plate may be still represented by 
the desmogen-strands which appear in development reaching 
from one foramen to the other (Fig. 12). Here then we have 
a seed in which the stone ends blindly below, and the water- 
supply for the nucellus is brought up round the outside 
and led through the foramina to the base of the free apex. 
These two foramina represent the ancestral chalaza, which 
by a strange evolutionary freak now finds itself close to the 
apex of the orthotropous seed 1 ! 
As for the integumental bundles of the ancestral type, 
these have dwindled down in Torreya and are represented by 
the spurs t. (Fig. 12). 
Finally, there is a temptation to wonder whether the 
peculiar ‘ digestive layer 5 of the nucellus which invests the 
embryo-sac may not be the palaeozoic tracheal mantle modi- 
fied to meet present requirements. Its pitted, mucilaginous 
character indicates that it probably performs some transfusion 
function in connexion with the water supplied by the tracheal 
strands which penetrate the foramina, whilst the nature of its 
contents suggests that it also plays a part in some metabolic 
process. Though the surface of the nucellus is coloured red 
in Fig. 12, thus emphasizing this view, the suggestion is ne- 
cessarily of the most tentative character. 
From what has been written it would seem possible to 
derive the very dissimilar seeds of a Cycad and Torreya from 
something approximately identical with the supposed ancestral 
1 The actual relations of base and apex in the seed of Torreya , as well as some 
matters of minor detail, would appear to have been misapprehended by former 
writers. Cf. C. E. Bertrand, Ann. des sciences nat., Bot., 6® ser., tom. vii, pp. 72, 
76, and PI. XI, Figs, i— 6 ; also Bull. Soc. Bot. de France, 18S3, p. 293. The 
same assertions appear in Renault’s Cours de bot. fossile, IV, 1885, p. 77. 
